Assessment of Optical Absorption in Carbon Nanotube Photovoltaic Device by Electromagnetic Theory

An electromagnetic (EM) scattering model is built for a kind of single-walled carbon nanotube (SWCNT) photovoltaic device excited by light. In this model, the exciting light is treated as classical EM wave with a very high frequency, and the SWCNTs in the device were treated as a lossy dielectric cylinder with frequency-dependent complex permittivity. Based on the EM scattering model, the Foldy-Lax multiple-scattering equation for the SWCNT cylinders can be derived, and then, the absorbed power of SWCNTs can be estimated. We also use EM simulation software - high frequency structure simulator (HFSS) - to extract the optical absorption of SWCNTs, and then the property of optical absorption of the device is studied more carefully; and the EM scattering model is also validated through HFSS simulation. From the results, some advices are given for the design of such kind of device.